Plug receptacle



NOV, 1, R KULKA 1,886,199

PLUG RECEPTACLE Filed May 6, 1926 lNVE -b d;

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Patented Nov. 1, 1932 UNITED STATES PATENT orricr.

' BUG-m B. 01' m YORK, N Y, ASSIGNOB T 0. D. WOOD ELEGIBIC 00., INC.,

01' m YORK, N. Y A CORPORATION OF NEW YORK rrm'a ancnr'racrn Application and m a, 1m. Serial m. 107,104.

Y My invention relates to a new and improved plug receptacle for electrical connections.

One of the objects of my invention is to make a device of great simplicity and which can be manufactured at minimum cost.

Another object of my invention is to de-- vise a plu receptacle which shall be very reliable and eficient.

Other objects of my invention will be set forth in the following description and drawing which illustrate a preferred embodiment thereof, it being understood that the above general statement of the objects of my invention is intended merely to generally explain the same and not to limit it in any manner.

Fig. 1 is a sectional view. Fig. 2 is a section on the line 2-2 of Fig. 1. Fig. 3 is a bottom view showing the cover osition. V ig. 4 is an elevation showingthe new and improved connecting screw.

Win

1g; 5 is an end view of the improved connecting screw.

Plug receptacles of the type to which my improvement is directed have heretofore included a body portion containing two or more contact blades, and a cover portion which was made thick and stron and of moldable insulating material. '1 's cover rtion was firmly pressed down upon the Eddy portion by means of screws which passed through the periphery of the cover and of the body portion. The pressure of the cover 85 when it was ap lied in position held the electric wires to t e inner ends of the contact blades. In devices of this type the manufacture of the shell and of the thick cover with openin in their peripheries for the purpose :1 ve mentionedwas quite expensive, and in addition, if the cover e loose, the electrical contact between the wires and the contact blades was injured.

Accordi to my invention, the cover con- I sists of a insulating material and a reliable contact between the wires and the contact blades is efiected wholly independently of the cover. As shown in Fig. 1, the body 10 of the r plug receptacle which is made of any suitable piece of fibre or other cheap the said inner end of each contact blade 12 consists of a tongue 14 spaced from a fork 13. The fork 13 isbent against and follows the contour of the adjacent ortion of the body 10, so that each fork 13 has an angular contour, the two branches of each fork 13 makingsubstantially a right angle with each other. Since each contact blade 12 is made of springy metal and has a main or body portion of a substantially U-sha ed contour, the two branches of each said b y portion being inclined to each other, this construction prevents any longitudinal movement of the blades 12, without the use of any special fastening means. For example, when the device is in the position shown-in Fig. 1, any downward movement of a contact blade 12 is restrained by the frictional grip between the of the inner endthereof.

As shown in Fig. 2, the shell or body 10 .is provided with lateral recesses 21 HIE-011%.

which the wires W can be led. Each wire is provided with the usual insulatin sheath and is provided with a naked end w ich can be located in a recess 15 of the shell 10, adjacent the inner vertical wall 16 of the shell 10. This recess 15 is an annular recess whose outer wall is 16 and whose inner wall is the outer periphery of the central perforated part of the shell 10. The outer wall 16 of said recess 15 projects beyond the inner wall of said recess 15, as shown in Fig. 1 and the cover 17 fits into said'outer wall. The naked end of each wire W can be placed intermediate the fork 13 and the tongue 14 of one of the contactblades 12, and then the tongue 14: can be firmly pressed against the wire so that the naked and of each wire W is firml clamped between the tongue 14 and the for 13 0 one of the said contact blades. The tongue 14 is shown in the drawing as occupying the position before the end of awire is clamped as above mentioned.

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Hence, the wires W are firmly held in position even before the cover 17 is applied to the body 10, so that the person using the device can be certain that the wires are properly clamped. When the blades of a plug member are inserted into openings 11, the blades of said plug member are inserted through the tops of openings 11 if the device is held in the position shown in Fig. 1. Hence, the top of shell 10 as shown in Fig. 1, may be considered as the outer or front end or portion, and the bottom of shell 10 may be considered as the inner or rear end or portion of the device.

The cover 17 is made of a thin piece of relatively inexpensive fibre provided with a central opening. The cover 17 has lateral lugs which fit into the recesses 21 of the body 10, so that any turningof the cover 17 is prevented. A countersunk screw 19 is located in the inner recess 18 of the body 10 and the shank of this screw 19 passes through a central longitudinal passage 20 and engages the internally threaded opening of the cover 17. However, the cover 17 need not be pressed against the shell with any substantial force, as it merely serves to cover the contact blades and does not clamp the Wires W into position.

It is obvious that the above device is very simple and reliable and can be economically manufactured.

As a further improvement and economy in the manufacture of my device, the screw 19 is made of a special contour so as to obviate the necessity for tapping the central opening of the cover 17, in order to provide it with an internal thread. Heretofore, in connecting a thin piece of fibre or other insulating materialto a screw, it has been necessary to first form an internal threading in the wall of the opening in the thin fibre plate or the like, by means of a tap, and an ordinary ma; chine screw having a fine pitch was employed merely for connecting the thin fibre plate or the like to the other'part of the device.

As this tapping operation was quite expensive, it was customarily omitted and the opening in the thin fibre plate was customarily made larger than the diameter of the screw, and the thin plate was held in position by means of an ordinary nut which was con nected to the screw.

According to my invention, the screw 19 is provided with an external threading having a fine pitch,.as in an ordinary machine screw. The end of the screw 19, instead of being fiat, is provided with a chamfered extension 19 and the threading on the screw is continued to form an extension 19 upon the chamfered end 19'. As shown in Fig. 4, the

extension 19 of the thread in the chamfered end 19' of the screw, does not exceed one complete turn. Otherwise, the device would act like an ordinary wood screw. If an ordinary wood screw were utilized for forming 'the thread on the internal wall'of the opening in the cover, it would be impossible to detach the cover from the screw and then replace it without again cutting a thread in the internal wall of the opening in the cover. However, by using a machine screw Whose shank is of uniform diameter, having a chamfered end provided with a short extension of the thread, the same effect is secured as though a tap had been used. Hence, when a hole is punched into the cover 17, which has substantially the same diameter as that of the main body of the screw 19, the insertion of the chamfered end 19 of the screw into this opening, together with a proper turning movement, forms a thread in the said opening which has a fine pitch, corresponding to the pitch of the threading on the screw 19. In other words, the screw acts as a combination tap and screw to first form the threading in the opening in the plate 17 and to then firmly fasten the plate or cover 17 to the body of the device.

I have shown a preferred embodiment of my invention, but it is clear that numerous changes and omissions could be made without departing from its spirit. Thus, I do not wish to be limited to the exact central location of the screw 19.

I claim 1. A plug receptacle having a body portion provided with contact blades therein, said body portion having an unthreaded opening intermediate said contact blades, a connecting screw having its shank located in a part of said opening, the head of said screw being wider than and being adjacent to said part of said openlng, an lnsulatmg cover for said body, said cover being made of fibrous material penetrable by said screw, said screw having an externally threaded shank provided with a chamfered end, the end of the thread of the shank of said screw extending into the chamfered end thereof, to an extent suflicient to cause said chamfered end to act as a tap for said screw to form an internally threaded opening in said cover which corresponds to the thread of said shank, said cover and said screw being held together by the cooperating threadings thereof, that portion of the thread of said screw whichextends'into said chamfered end not exceeding a complete turn. v

2. A plug receptacle comprising a body portion having contact blades therein, the said body portion having a cover provided with an opening whose wall has a thread formed therein, and a screw located in said body portion and adapted to fasten said cover to said body portion, said screw having a substantially cylindrical body provided with a chamfered end, said screw having a thread whose end is locatedon the wall of the chamfered end of said screw for a distance not exceeding a complete turn so that said end of the thread can act as a tap to form said sesame threading in the wall of the opening of said cover. a 4 3. A lugreceptacle com rising a body rtion avmg a plurality contact blades 5 coated in opemn communicating with the front face of sai body portion, said openings communicating with a rear annular rece'ss in said body portion, the rear end portions of said blades be g ada ted to contact with respective wires, said y portion havmg a rear peripheral wall, said wall ha recesses intermediate said contact blades, a-

v rear'detachable cover for said body portion havin lugs adapted to engage said ast-menll tione recesses to prevent the turning of said cover and a connecting member detachable and spaced from said annular recess and extending wholly through said body portion and also through said cover and adapted to 9.0 connect said cover to said body portion.

4. A plug receptacle comprisin a body portion having a central lo 'tu 'nal unthreaded opening adapted to ve a screw loosely located therein, said body portion also having longitudinal openmgs communicating with the front face of said body portion contact blades located in said openings, sai

openings communicating with a rear annular recess, the rear end portions of said blades adapted to contact with respective wire said body portion having a rear wall, wall havln recesses intermediate saidblades I to admit t e wires, a rear detachable cover for said bod rtions having lugs adapted 85 to engage sai last mentionedreoesses, the

said cover having an internally threaded osenin the rear end of said screw being a ap to engfie said opening to secure the cover to said portion.

40 Intestimony w ereof I ah mkgfiixire.

- EUGEIJE R. 

